I've never really had a paladin as my main. However, I've tried three times. The results are an belf 63 pally on my home server, and a dwarven 30ish paladin and a belf 80 paladin on two other servers.
I've run into two problems with paladins, time and again. The first have been that the playstyle of protection and retribution have been incredibly boring. It looks like that's going to change in Cataclsym.
The other problem is the very theme of a paladin... protector of the innocent, bringers of pure light, yada yada, self-righteous bastards. I don't like the concept much. Part of the reason is of course that I hated paladins as horde during classic. Old habits die hard.
When Blood Elves could be paladins, it helped a lot, since the idea was that belfs just (ab)used the power for their own, egoistical purposes. A concept I can much more easily relate to. However, they use the same names for their spells. Hm... perhaps if I just renamed them for my own benefit?
I'd like to briefly tell you what I don't like about the theme. I may step on, probably even stomp on, some toes here.
The concept of paladin reminds me far too much of the middle-age Catholic Church. And from history, that lead to a lot of bad stuff. The worst part of it was when people with no conscience used people who only wanted to do good as pawns for their plans.
Take the Crusades, for example... lots of good people died, an even greater number of people got abused, and a small number of people reaped a lot of benefit from it, with malevolent intentions from the very beginning.
I also firmly believe that humans are creatures controlled by hormones and chemicals. There's a saying which I'll rephrase from memory: "A man is only rational for a total of about one hour each day." It captures what I believe in.
Yes, people want to be rational, but most of the time, they aren't. A lot of people are prepared to rationally accept a life in celibacy. However, most people will eventually fail because their very genes constantly urge them towards reproducing. When they succumb to their desires, since it is not openly accepted, it must happen in secret, and often lead to very tragic fates on the other end.
I believe in open communication, for a lack of a better term. Being open to communicate with others are the very premise of any working relationship, both between family, lovers, friends and enemies. In the case of enemies, a "working relationship" may be seen as a state in which you respect each other's borders, even if you don't like the other side.
There still need to be work beyond having open communication to actually make a relationship work. However, if you fail to communicate, the relationship is almost guaranteed to fail. Many live constantly in failing relationships, and it works because one side is dominating the other. For any sort of relationship where the two sides want to be on equal terms, communication is the key.
If you feel offended after reading this, I'm all open for discussion.